Latch mechanism for carry type scraper ejectors



Nov. 6, 1951 c. A. GUSTAFSON 2,573,765

LATCH MECHANISM FOR CARRY TYPE SCRAPER EJECTORS 4 SheetsSheet 1 Filed May 24, 1947 INVENTOR. Car/A. 6L/f71fffl/7 64 142+? ATTORNEY Nov. 6, 1951 c. A. GUSTAFSON 2,573,765

LATCH MECHANISM FOR CARRY TYPE SCRAPER EJECTORS Filed May 24, 1947 4 Sheets-Sheet 2 EJECTOR IN V EN TOR.

ATTMNEY Nov. 6, 1951 c GUSTAFSON 2,573,765

LATCH MECHANISM FOR CARRY TYPE SCRAPER EJECTORS u Filed May 24, 1947 v 4 Sheets-Sheet 3 IN V EN TOR.

BYCdr/ Glff7 dffal? ATTORNEY Q 1951 c. A. 'GUSTAF'SON 2,573,765

LATCH MECHANISM FOR CARRY TYPE SCRAPER EJECTORS Filed May 24, 1947 4 Sheets-Sheet 4 IN VEN TOR.

ATTORNEY Patented Nov. 6, 1 951 V asveg'zes I LATCH MECHANISM For CARRYITYPEI I I I SCRAPER EJECIOR'S Carl A. Gustafson, Peoria, Ill., assignor to Gater-. pillar Tractor 00., San Leandro, Calif., acorporation of California Application May 24, 1947, Serial No. 750,284

This invention relatesto control mechanism for earth moving scraper'sand the like and particularly to such mechanism on a scraper having a bowl with a movable-front apron and a movable ejector adapted to be selectively controlled by a single cable. I

' One type of scraper now commonly employed for collecting and moving large quantities of earth and the like comprises. a large bowl or body member with a draftrconnection by means of which it may be connected to and drawn by a tractor unit. The bowl-is provided with a scraper edge adjacent its rorward'portion and may be'lowered to bringthe scraping edge into contact with the ground to effect collection of earth deposited in the bowl. Therear wallof the bowl is formed as an'eje'ctor and is movable forwardly to empty the bowl of its contents when it has been drawn to a. proper place for'discharge of earth that has been collected. The front of thebowl' is normally open ror'the' reception or collection of earth and isprovided with a gatelike-device usuallyreferred to as an apron which can be swung: downwardly or closed during transportation of aload of earth and which is usually partially closed during the. scraping or loading operation to control the filling of the bowl with earth in am'anner well known to those familiar with this art.

The operation of theejector and of the apron as well as the operation of raising and. lowering the bowl and its scraping edge with relation to the ground are all desirably controlled by the operator of the tractor and control means are conveniently provided for this purpose including cables leading between "the tractor and the scraper. The cables are usually wound upon drums carried by the tractor and'adapted to be rotated 'b'y a suitable power take-oil shaft so that the cables may betaknin or payed out as required.

In this kind of scraper a single cable controlled from the tractor is employed for raising the apron and for advancing the ejector. The ejector is normallyheld in a retracted position by resilient mechanism such as a nest of springs or a pneumatic devicet The arrangement is. such that by exerting a pull ron'the single-cablethe apron is first raisedand then. with the apron fully. raised the ejector isnzadvanced' to discharge the contents of the bowl through its 'owen front end; This requires heavy sprinesin rder to tairi the elector in its, retracted position. during manipulation olf=;the apron so that-when-the ejector :is advanced: the pull required tooverc'cme 2 Claims. (Cl.-37- -129).

the tension of thesprings is excessive and springs are often-over-stressed. It is; therefore, an object of this invention to" provide a scraper of the kind described wherein the ejector return springs are relatively light and flexible to afford justsufiicient force to retract the ejector after it has been advanced and to provide-means separate fromthe springs to latch the ejector in' its retracted position-during operation'of the front apron; A further bject of the invention is to provide-a scraper with an apron and an" ejector, and a latch-means on the-ejector to hold it in itswretracted position, the" latch being rleasableonly when the apron has been fully raised. Further-and more specific objects of the invention and==t1re manner in-which these objects are attained will beflapparent fromthe following specification wherein the scraper einbodying the invention is disclosed in detail. I In the drawings:

Fig. 1 is a view inside elevation with parts in section of a scraper embodying the present in vention and illustrating the scraper asdrawnby a tractor the rear portion of which isalso shown; Fig. 2 is-a-schematic view illustrating thecablc control of the apron and ejector of the scraper shownin Fig. 1 j Fig. 3' is an enl-arged vertical section through litt he rlear portion of thescraper" illustrated in 1g Fig-,4 is an enlarged detail of a latch mechaa nismshown in Fig; 3;. L Fig. 5 is an enlarged fragmentary view-illus trating the latch mechanism in plan; Fig. 6 is an enlarged seetion taken on line VI+= -VI of Fig. '5; and Fig; '7 is a section taken on line VII-VII. of

Fig.5.-" r I Referring first to'Fig: 1 of the drawings, a scraper of the type with which the present im venticn is-used is generally, indicated" 'at H)- as having a-main bowl portion including a pairof spaced side-plates ll and-a bottom-l2. The for ward edge of the bottom I2 is provided with. a scraping blade l3 The scraper bowl is supported adjacent its 'rear end by a pair ofigroundengaging :wheels l 5 and by a; pivoted-draft connection, generally indicated at "5-, at its forward end The draft connection l6 comprises a pair-01; spaced hollow arms ll'pivotally connectedone to eachside of= thebowl- Ill-as by pins Ha; At their, forward ends, arms ll are connected by a cross member 18 of hollow tu-bular construction, and. a draft arm la, extends forwardly irointhecross member 18 and: is: adapted to beconnected at lts the forward end with a suitable universal pivotal connection 28 carried by the rear end of a tractor partially shown at 2|. The tractor 2| also carries a cable control unit of conventional construction which takes power from a rear power take-off shaft of the tractor and includes a pair of cable-winding drums one oflwhich is indicated in dotted lines-at 22. The function of the drums 22 is to take in or pay out cables for con trolling the operation of the scraper. For example, in the present case, the scraper bowl I8 is adapted to be raised or lowered about the axis 01' its supporting wheels IS in order to control the position of the blade l3 with respect to the ground. This raising and lowering of the scraper is accomplished by a cable 24' secured to and wound upon one of the drums 22. The cable 24' 4 with a rearwardly extending carriage 35, shown as an inverted U-shaped beam. This carriage 35 is supported for reciprocating motion with relation to the scraper bowl in a guide frame 36 which extends rearwardly of the bowl. Guide frame 38 forms a part of the scraper bowl and is supported by a pair of transverse-beams 38 and 39 extending between and secured to the sides ll of the bowl, further support being provided by transverse beam 48 and a pair of longitudinal beams 4| (Fig.3). A pair of similar downwardly inclin'edfbeams 42 extend rearwardly from beam 38 and meet with transverse beam 48 and longitudinal beams 4| as shown, the beams 42 serving to support axle assemblies 43 of wheels l5.

-. to be moved forwardly with respect to the bowl leads from its drum 22 over a cable-laying sheave indicated at 23, then around a guide sheave 24 and upwardly through the hollow center of a part of the universal connection 28 and over a guide sheave 25 disposed above such connection. From the guide sheave 25, the cable 24' leads rearwardly to pass over a guide sheave 26 on the draft connection and is then led around two groups of' sheaves, one indicated at 2! as carried by theforwardend of the scraper bowl and the other indicated at 28 as carried by the draft connection, and is finally secured at its end 'to the draft connection adjacent the sheaves 28. Con sequently, the forward end of the bowl can be raised or lowered upon taking in or paying out of cable 24' and as the bowl'raises or lowers, it will: pivot about the axis of its supporting wheels 15.- Pivotal movement will'also take place about the pins l'la oi arms I! and at the universal draft connection 28. In operation, and when the bowl is to be filled, it is lowered until its scraping edge touches the ground and, as the tractor draws the scraper forwardly, the earth engaged by the scraping edge will be depositedin the bowl in the usual manner. 'When thebowl is filled, or when a particular' scraping operation is completed, it may be raised by manipulation of the cable 24' and will then serve as a conveying or transporting unit drawn by the tractor for carrying the earth orother material contained by the bowl to any desired point for discharge.

The bowl is provided with a front gate or apronj'indicated at 38, which maybe closed to prevent the earth fromspilling 'as it is being transported. The apron also serves the purpose, when partially closed, of regulating the amount of earth that can pass into the bowl over the scraper edge during a scraping operation. This apron 38 is carried by'a pair of arms 3| pivoted as at 32 to the sides I l of the bowl so that it may be-swung upwardly to its open position as illustrated'in-Fig. 1 or lowered to a closed position. Thiposition-ofthe apron 38 is also controlled by a cable adapted to be manipulated by the operatorof the tractor 2| in'a manner presently to be de'scribed.

'The rear wall of the scraper bowl I8 is generally indicated at 33 and is supported to move forwardly with relation to the sides and bottom of 'the'bowl'to serve as an ejector for the purpos of discharging the contents of the bowl forwardlyoverftheedge of the blade l3 when the apron 38 is in its raised position. The ejector which servesias therear wall of the bowl when it is in its retracted position is best illustrated in Figiilf o f the drawings as being made of spaced reinforced plates 34. The ejector is provided 18. The ejector is guided in such movement by rollers'48, 41 and 48. Rollers 46 and 41 engage rails 58 and 5| respectively which form a part of the scraper bowl while the rollers 48 engage suitable rails that, form a part of the guide frame 36. v

It is desirable that the operation of the apron and ejector be individually controlled to the extent that the-apron 38 may be raised and lowered independently of, or at least without advancing the ejector 33. The ejector should also be capable of operation or of being advanced to discharge the contents of the bowl while the apron is raised and without moving it from it fully raised position. To accomplish this, a single cable is provided which may be paid-out or taken in' by the operator of the'tractorand upon taking in on this cable the apron 38 is first raised. When it obtains its fully opened position, as illustrated in Fig. 1, and only after it has obtained such position, continued taking in or pulling upon the same cable effects advancing oi the ejector 33 to discharge the contents of the bowl: One of the advantages ofv this manner of operation is that as the scraper is engaging the ground and the bowl .is being filled, the apron may be raised and lowered to vary the opening above'the blade I3 and thus to determine the rate and the manner in'which the earth being scraped enters the bowl. This adjustment of the apron may be accomplished entirely independently of the ejector 33 so that it does not cause the ejector to advance forwardly in the bowl. Furthermore, after the apron is fully raised and the ejector starts its :forward movement for the purpose of ejecting the contents of the bowl, there are times when large slabs of rock or other hard materials contained by the bowl become wedged between the blade and the lower edge of the apron 38, and the operator must permit retraction of the ejector 33, at least partially, to permit such obstacles to settle or readjust themselve in the bowl before they can be discharged. This can be accomplished without disturbing the position of the apron. l

The manner in which this mechanism operates is most clearly illustrated in the diagrammatic view shown in Fig. 2 and must be understood in order to appreciate the advantage of. the present invention-a In Fig. 2 the cross'member l8 and the arms I! are indicated in simple outline: A cable 68, one end of which i secured to one of the drums 22 of the tractor, leads over guide sheaves 24 and '25 similar to the manner of cable 24 and enters the tubular cross member I8 through a tube 6|, shown in Figs. 1 and 2 of the drawings asextending forwardly through the structure of ti'e'd aft conn ction 19; IWithinthe drum 18 the :eable .6.0 passes over .a;g.uide sheave 162, :then :over

-a guide :sheave -63, after which it is trained :over the sheaves in a movable or sliding block 94 and gtheqsheaves-in a stationary-block e55 :the cable -30 is taken in, .it' tends to -advance the, block @655 toward the-block 55 with a mechanical advantage determined by the :number :of strands-disgposed between the two blocks; After passing through the sheaves on the blocks stand .65, the cable'lifl :is 'carried downwardly through one :01 the side 'arms i"! of :the draft assembly-and passes outwardly through the rear end :bf'th'e arm over :guide sheave 'fi-Fl and #then =overlsheave 168,:and then inwardly of the "bowl memes the ejector 33 where .it is trained rover 2a :nheaveifiii. llilrom the sheave G9nthe cablecis :led. a series :01? sheaves "I! 9 :secured :a marwamdly "ex tending housing Ill of ejector. ((iliig'. r3 and a series of sheaves 1'2 secured with relation fto the bowl. 'The end .of the cable is made fast, as indicated at 14, to an anchor on the bowl, Thus, taking in or pulling on the cable 69 shortens the distance .between the sheaves, it :on the ejector and the sheaves F2 on the bowliso that the ejector will tend .to move forwardly in the bowl.

The apron 3B is raised 'by a pull on a cable which, as shown in Fig. l ir secured to the :apron :by an anchor 1t, and leads over afgui'de sheave 1?! disposed "in a sheavel tower {Fflkonthe draft assembly and thenpasses finto thei -cross member i1 8 through an opening 19, wherein-it is guided over sheaves 9B and 8| and secured at its end to the sliding block 64. Because of the connection just described, any taking up or pulling on the cable 69 tends to shorten the distance between the blocks 64 and 65 and thus, through the cable 15 connected to the block 64, to raise the apron 39. The same pull on the cable 60 tends to shorten the distance between the sheaves 10 on the ejector and sheaves 12 on the bowl and thus to advance the ejector to discharge the content of the bowl. Raising of the apron is resisted by gravity, and forward movement of the ejector is resisted by spring action. Taking into consideration the normal resistance to the operation of the apron and the ejector and also the mechanical advantage that is obtained by the cables 60 passing over the blocks which control the operation of each of these members, the system i balanced in such a manner that the apron will raise more easily or with less force applied to the cable so than is required for advancing the ejector. Consequently, when a pull is applied to the cable 6!], the block 64 will be advanced toward the block 65 as far as possible and will effect full upward movement of the apron 30 before the continued 'pull on the cable is effective to advance the ejector. Furthermore, as the ejector is returned by spring action upon paying out of the cable, it should attain its fully retracted position before the apron 30 start to close.

The springs employed for retracting the ejector are shown at 89 in Fig. 3 as disposed within the guide frame 36. They are secured to an anchor member 8! on the ejector at their forward ends and to a similar anchor 82 at their rear ends. The anchor 82 is carried by a plate 83 spanning the outer ends of the beams 49 of the scraper bowl.

Difficulties have been encountered in the operation of a scraper of this kind because of the fact that the springs 89 must be extended a considerable distance to accommodate the forward movement of the ejector, which in a large scraper :sometimes amounts to. -:several feet. :If-sthese zspri'ngs sare .ESliifi :enough tolretain the e'jector iitsn'etracted :position during :raisi-ng and lowering roperations 10f "the apron, it is :found' that they :are over-stressed :or extended beyond their elastic limit when :the ejector is :moved :forwardl y throughout the 'fullextent of its intended travel. Consequently, according to the "present "invention the :springs are .made "considerably lighter 'than'is usual practice andijust suiiiciently. strong to ensure the "return of the ejector from its adwancedpositionbut not to overcomeithe tendency wofi the ejector :to ibe pulled forwardly by'th'e cable 60 .as the :apronzislbeing raised and lowered.

In order totprevent pperation .of the ejector by aapull on the cable except when the apron is in its :fully :opened position a latch smember, shown at 18.5 :in Fig; :3, "is carried lby .th'e scraper bowl and :has .a roller 386 at its end engage'able with either of notches 8! or 88 on a latch-plate 99 secured to and carried by the housing 1 which zis a-rpart of the ejector. The latch 85, best illustrated in Figs. 4 and .5, is carried on a shaft 99 rotatably supported :in brackets 9| secured to and extending rearwardlyfrom .the cross member 38 .of the scraper. A lever 92 is vnonrotatably se- .cured to one outer end of the shaft 90 and is urged in a counterclockwise direction against an adjustable stop 93 by means of a spring 94 anchored atone end relative. to the scraper bowl. The spring 94, therefore, serves to retain the latch in a down position where it will intercept the notch 81 on the plate 89 to prevent the ejector from being.pulled forwardly.

In order to raise the latch and permit the ejector to be pulled forwardly when the apron has attained its fully raised position, the end of the cable 60 instead of being anchored to the bowl as shown at 14 in Fig. 2 is anchored to a lever 95 fixed to one end of the shaft and limited in swinging movement by a fixed stop 96. When the apron is raised and a suflicient tension is applied to the cable 60 the lever is drawn downwardly, as illustrated in Fig. 6, or in a clockwise direction to rotate the shaft 90 against the tension of the spring 94, thus raising the latch 85 and permitting the ejector to move forwardly under influence of the cable 60 in the manner previously described. When the tension on the cable 69 is released and the ejector is retracted by its retracting springs 80, the latch 85 will, of course, assume its normal downward position and the roller 85 on its end enables it to roll over the inclined approaches to the notches 81 and 88 until it again assumes the position illustrated in Fig. 3. As some clockwise direction of the lever is necessary in order for it to pass over the notched plate 89 upon retraction of the ejector and, as the spring 94 is too stiff to permit this action with ease, the lever 85 is preferably mounted for limited rotation on the shaft 90 but has an outwardly projecting lug 97 on one side (see Figs. 5 and. 7) engageable with a stop member 98 secured against, rotation on the shaft 99. A soft spring 99 carried by the stop member 98 overlies the projection 9'! and permits the lever to move upwardly or in a counter-clockwise direction sufliciently to enable the latch plate to pass beneath it.

With the construction described relatively light springs may be employed for retracting the ejector mechanism so that they will not be overstressed or permanently distorted as the ejector is advanced. At the same time the raising and lowering of the apron, which places some stress on the cable B0, will not effect forward movement of the ejector unless and until the apron has attained its uppermost position and the pull on the cable 68 is sufficient to overcome the tension of the spring 94, the action of which normally retains the latch 85 in its latching position. It

is possible in some cases that the ejector will not be fully retracted by the springs 80, as, for example, when a large rock or other material becomes lodged in the scraper bowl behind the ejector. In this event the latch 85 may come to rest in the advanced notch 88 rather'than in the notch 81 and will still serve to retain the ejector against undesirable forward movement during manipulation of the from; apron. Ordinarily, however, when this occurs the load of the earth in the bowl as it is being filled urges the ejector rearwardly with sufficient force to overcome whatever obstructs its rearward movement; and the latch 85 will then come to rest behind the proper notch 87.

I claim:

1. In a scraper having a bowl'for the reception of earth and ejector mechanism for discharging earth from the bowl, latch means for holding the ejector mechanism in inoperative position comprising a shaft rotatably carried by the bowl, a latch lever supported for limited swinging movement on the shaft and engageable with the ejec- F engaged position, and means to turn the shaft in opposition to said second resilient means for releasing the latch.

2. In a scraper having a bowl for the reception of earth and ejector mechanism for ejecting earth from the bowl, means to latch the ejector in'an inoperative position comprising, a rotatable shaft on the bowl, a latch lever supported for limited swinging movement on the shaft, a notched plate on the ejector mechanism engageable by said lever, a spring acting between the shaft and the bowl to bias the shaft and lever toward the position of latch engagement, means operable upon the application of force to operate the ejector'to rock the shaft in opposition to said spring, and resilient means acting between the shaft and the lever to permit retraction of the lever sufficient to enable latching action without flexing said spring.

CARL GUSTAFSON.

REFERENCES CITED The following references are of record in thefile of this patent:

UNITED STATES PATENTS 

